Gender Split

bar_slider = alt.Chart(df).mark_area().encode(
    x='Year',
    y='Population (historical estimates)',
    color ='Country'
).properties(
    height=300
).add_selection(select_year)

employ_scatter = alt.Chart(df).mark_circle().encode(
    x='Depression (%)',
    y='Employment rate',
    color = 'Country',
    opacity=alt.condition(
        select_year,
        alt.value(1), alt.value(0.1)
    )
)

#best_line = scatter_plot.transform_regression('Depression (%)','Employement rate').mark_line()

(employ_scatter) & bar_slider